Often in manufacturing process industries such as cement industry, paper industry, metallurgical process industry, certain processes can produce various grade of product across a span of time. For example, in paper manufacturing, by modifying the relevant process variable, various grades of paper can be produced over a period of time. The term “grade” identifies a set of product specifications, such as sheet weight, sheet calliper, sheet brightness, sheet colour, etc. The process in which the process line, which is initially configured to produce sheets of one specification, is transitioned to produce sheets of another specification is referred to as a grade change or a transition.
Conventionally, in terms of control philosophy such transitions are defined as a change of output parameter of a process due to a notable shift in the operating point or parameters of the process. The shift or change in the operating point by the plant control that is interfaced with the various controllers and other devices in the plant. Specifically, the plant control system automates the operational set points of various functional components of the continuous process to ensure the product is produced in accordance with the new product specification identified by the grade change or transition.
While control of processes in steady-state are well-established and are effectively and efficiently performed by conventional control systems, such control systems offer inadequate performance when used to control processes having a plurality of transitions.
Therefore, there is a need for a system and method that can effectively control processes having one or more transitions.